The invention relates to the production of electrical conductors of measured length and it is concerned more particularly with the cutting of such conductors from a continuous supply wire.
Apparatus for producing electrical conductors from a continuous supply wire have heretofore been developed in which a bench type main frame is provided at one side with a pair of parallel, spaced apart side frames extending transversely of the main frame; in which laterally spaced endless chains of a wire propelling conveyor are mounted, respectively, on the side frames; and in which a wire feeding mechanism and a wire cutting mechanism are mounted on the main frame and are operated in such a manner as to successively cut wire portions of measured length from the supply wire, and place them on the chains of the wire propelling conveyor for step by step sidewise advance movement by the latter away from the main frame. In order to provide for the production of conductors of different lengths, the side frame next to the wire cutting mechanism is rigidly connected to the main frame, and the other side frame is laterally adjustable to fixed positions at different spacings from the fixed side frame.
In prior art apparatus of the above outlined type auxiliary equipment such as insulation stripping units and terminal attaching units are usually mounted on the side frames and perform their functions on the conveyor supported cut wire lengths during intermittent periods of standstill of the conveyor.
In order to feed the wire, as mentioned, across the spaced conveyor chains a pair of counter reciprocating feeding clamps have heretofore been used which function alternately to advance wire stock through a cutting zone; and the cutting mechanism has been operated to sever the advanced length of wire from the stock after each feeding stroke of each feeding clamp. The length of the wire which is thus cut from stock after completion of a clamp feeding stroke is determined, not only by the length of said stroke, but also by the catenary sag which the wire assumes in the space between the conveyor chains before it is cut. If the spacing between the side frames and therefore of the conveyor chains is large and the wire is relatively heavy, the catenary sag of the wire will, of course, be greater than when the spacing between the conveyor chains is short and the wire is relatively light. In other words, the length of the wire which is cut from stock is subject to variation which in cases where extreme accuracy of the cut off wire length is required becomes objectionable.
Also, in apparatus of the mentioned character employing a pair of counter reciprocating wire feeding clamps relatively complicated and expensive mechanisms have been required to precisely time the opening and closing of the feeding clamps and operation of the wire cutting mechanism so that it will sever the supply wire at the exact moment when a feeding stroke has been completed by one feeding clamp but not before the other feeding clamp has taken hold of the uncut wire. An apparatus which is constructed and operated in the above outlined manner is disclosed in U.S. Pat. No. 3,701,301 issued on Oct. 31, 1972 to Ragnar Gudmestad for Wire Length Measuring and Cutting Apparatus.